1. Field of the Invention
The present invention relates to a system for interconnecting services of wired and wireless phones, and more particularly, to a system for interconnecting services of wired and wireless phones wherein a subscriber using a wired phone service is provided with portability and a method for processing a call.
2. Description of the Related Art
Generally, a conventional public communication network can be divided into a wired phone service network and a mobile communication phone service network. The wired phone service is provided with the aid of a public switched telephone network (PSTN), and a wired phone terminal is connected to a telephone station using a telephone line. In the case of the wired phone service as described above, portability cannot be provided since the wired phone terminal is connected to the telephone station using the telephone line. Of course, even though a wireless phone performing a wireless communication with a main body of the wired phone terminal using a 900 MHz (megahertz) wireless bandwidth is being used, there is a problem that its portability is largely limited compared with the mobile communication terminal using the mobile communication service.
On the other hand, the mobile communication service is provided with the mobility using a Public Land Mobile Network (referred to as ‘PLMN’, hereinafter). The PLMN includes a Mobile Switching Center (referred to as ‘MSC’, hereinafter) which takes charge of a mobile communication service in an arbitrary area, a Base Station Controller (referred to as ‘BSC’, hereinafter), a Base station Transceiver Subsystem (referred to as ‘BTS’, hereinafter), and a HLR/VLR (Home Location Register/Visitor Location Register). The CDMA (Code Division Multiple Access) collectively indicates wireless environments which take charge of mobile communication services in another district.
The MSC performs connection and control of a plurality of BSCs connected to the MSC to other MSCs in the PSTN or PLMN.
The BSC performs functions of wireless link control and handoff, and the BTS performs functions of constructing a wireless communication path together with its communication service area, that is, a wireless terminal included in its cell area and managing a wireless resource.
In the HLR/VLR, the HLR performs functions of subscriber location registration and a database for storing subscriber information, and the VLR is a database which temporarily stores information of an MS existing in a cell area of which a corresponding MSC among a plurality of MSCs takes charge. When the MS moves to a cell area where other MSCs manage, information stored in the corresponding VLR is removed.
Even in the case of the mobile communication phone service using the PLMN, it does not interconnectively operate with a wired phone terminal using the public switching telephone network so that there occurs a problem that each service operates independently and does not have interrelationship.
On the other hand, even though the mobile communication service can be generally serviced everywhere without being restricted to an area such as premises, that service can be provided by only using the mobile communication service system and a wireless communication cannot be provided without special billing in an established area.
That is, in order that a wired phone service terminal using a wired phone service communicates with a mobile communication terminal of the mobile communication service subscriber, a method was used, where each terminal is connected to the PSTN through each exchange and connects a call to the other terminal.
Here, the PSTN includes the PLMN and PSTN. Accordingly, there was an inconvenience that an accounting was charged even when a wired communication subscriber and a mobile communication service subscriber were communicating in the same building or apartment complex.
Furthermore, in the case that a subscriber is simultaneously provided with wired phone and mobile communication services, there was a problem that the communication service fare was burdensome since the subscriber has to pay for in each of communication fares.
Furthermore, in the case that a subscriber is simultaneously provided with wired phone and mobile communication services, and other party knows one number of the two phone numbers and makes a call to the corresponding terminal, there was an inconvenience that a communication connection could not be achieved when the subscriber could not respond to the call with the corresponding terminal even though the subscriber had another terminal.
Of course, when a call for an arbitrary terminal is made, the call can be transferred to another terminal using a call terminating service. However, there was a problem that the service can be provided when it has been previously established, and only the terminal to which the call terminating service has been assigned is called when the service has been assigned.